This invention is generally directed to information handling in a telecommunications system in which different non-predetermined modes of communication can be utilized by the originating user for a communication channel. More specifically, this invention is directed to automatic adoption of the user's communication mode for sending call routing and feature selection messages to the user.
In a telecommunications system, such as the public switched telephone network (PSTN) in the United States, the most common communication mode consists of a conventional voice call between two users. It is apparent that for a conventional voice telephone call, the parties must have the capability to speak and hear. The PSTN also supports other communication modes employing various forms of amplitude and phase modulation. Telecommunications systems accept user input via dual tone multiple frequency (DTMF) tones following initial call completion to permit the user to make selections in response to a voiced menu of choices such as in incoming call routing used by a company to direct calls by subject matter.
A telecommunications device for the deaf (TDD) is available to provide communications with the hearing impaired. This device includes a keyboard and a screen display which permits the hearing impaired to communicate over conventional telephone lines by transmitting and receiving alphanumeric characters via digital communications using a Baudot code which is well known. A party communicating with a person using a TDD must either use a TDD or utilize an operator having a TDD as a translator between the TDD communication mode and conventional voice communications. For a heating impaired person using a TDD to place a call to a party who is not hearing impaired and does not have a TDD, the hearing impaired originates a call to an operator with TDD capability at a predetermined number. The originator communicates the number to be dialed by the TDD to the operator who places a conventional call to the other party. The operator translates the text received on the operator's TDD screen into voice communications to the other party and translates received voice communications from the called party into text by typing the information on the operator's TDD. The originating party then sees the information displayed on his TDD screen. A TDD user must normally call a predetermined operator assistance number in order to reach an operator having a TDD; telephone operators which provide general assistance may not have access to a TDD.
An increasing number of features and services are provided via the PSTN. Call routing functions and automatic response systems typically utilize DTMF tones such as generated from a Touch-Tone telephone pad in response to a voice message prompt or menu. Current automatic call processing systems require that the party be able to understand a voice prompted message and that the party be able to respond with appropriate choices utilizing DTMF signaling. Failure to provide an appropriate DTMF signaling reply within a predetermined time typically causes the call to be routed to the called party's operator for further handling. This permits nonhearing-impaired users without access to DTMF signaling to utilize the system. However, a hearing impaired person cannot take advantage of such an automatic recognition system because of the inability to understand the voice message prompt.
Modem communications over the PSTN is increasing with the widespread use of personal computers. Conventional modems which comply with established Bell and CCITT standards transmit and receive tones which are digital representations of alphanumeric characters in accordance with a defined ASCII data format. Communication mode problems do not exist for direct calls when the calling party and the called party each utilize compatible modem communications. PSTN operators are not normally equipped with modem communications equipment and hence, operator assistance will require a user to switch to voice communications rather than modem communications for such assistance. Although both TDD and modems utilize tone signaling, the formats and techniques differ and hence, are not compatible.
Them exists a need to provide more flexible telecommunication services which will accommodate different communication modes.